Various collector or accumulator apparatuses have been and/or are utilized for the collection and subsequent advancement of sheet articles comprising paper sheets, documents and the like such as those typically utilized in high-speed media processing such as, for example, mail processing.
One such collector apparatus and method utilizes a front stop/pusher carriage for advancing a set or stack of collected sheet articles into constant running nip rollers which handle and further advance the collected sheet articles. Another collector or accumulator apparatus and method that has been used in the past uses over and under continuously running round belt drives to advance sheet articles into clutch-actuated nip rollers. Yet another common collector apparatus and method uses flat belt drives and solenoid-actuated drop rollers to convey collected sheet articles into constant running nip rollers. These apparatuses and methods all suffer from the disadvantage of shingling of the set of collected sheet articles which can occur because of the nip rollers as well as from the problem of toner sometimes being transferred from the nip rollers to the processed material.
A collector apparatus and method used in the past which does not require the use of nip rollers is a Vacuum Sheet Sequencer device comprising a two belt system wherein each belt has two spaced-apart lugs fixedly attached thereto and the system is driven by a clutch brake system. One lug of each belt simultaneously acts as a front stop for collected sheet articles. Advancement of the collected sheet articles occurs by each belt simultaneously cycling such that the lugs acting as front stops move forward in the advance direction and out of the way of further advancement of the collected sheet articles by movement dictated by the belts. Since each belt has two lugs attached thereto, the other lugs of each belt simultaneously move to push the collected sheet articles from their previous stop position and stop in a position for providing a stop for subsequent collected sheet articles. Since the lugs are fixedly attached to the belts and therefore all cycle simultaneously, this system typically is adapted for collecting and advancing sheet articles of a certain predetermined dimension or size and therefore suffers from such disadvantage.
Another problem with prior art collector apparatuses and methods such as those described hereinabove is that they have a limited capacity regarding the number of stacked sheet articles that can be collected thereon and subsequently advanced therefrom. Typical prior art collector apparatuses and methods have at best a limited capacity or ability regarding the number of sheet articles that can be collected and advanced as a stack as such prior art apparatuses at best typically can only collect and advance a stack of up to approximately twenty-one (21) sheet articles. To compensate for such a limitation, large sets or stacks of sheet articles have had to be broken up into various subsets for processing.
In view of the problems associated with prior art collector apparatuses and methods, it can therefore be seen that much room for improvement exists in the art of collector apparatuses and methods for an improved collector apparatus and method with an ability to collect and advance large stacks of sheet articles of various dimensions or sizes in an improved manner.